Brake shoe



Nov. 14, 1933. A NELSON 1,935,330

BRAKE SHOE Filed July 7, 1931 172 Me 72 f0 7". 4 4/3 Patented Nov. 14, 1933 BRAKE SHOE Albert Nelson, Chicago, Ill., assignor to The American Brake Shoe and Foundry Company, Wilmington, Del., a corporation of Delaware Application July 7, 1931 Serial No. 549,169

' '1 Claim. (01. 1ss' 24s) Thisinvention relates to brake'shoes of that type whichare provided with a reenforcing back plate an'd'with an attaching lug located midway between the ends of the shoe.

The object of the invention is to reduce wear between the shoe attaching lugs and the projections on the brake head, toprovide an additional lug of novel construction to cooperate with the usual center attaching lug and provide therewith an enlarged lug bearing on the head, to make the shoe interchangeable end for end on the head, to make the additional lug of the strap lug type and provide a high keyway opening therein to accommodate the fastening keyQand to locate the strap and construct. the body projections which reenforce the strap so that the shoe member may be "used in different kinds of heads and 7 seat properly therein" and avoid undue wear on the head. 1 In the accompanying drawingillustrating a selected embodiment of the invention Fig. 1 shows a shoe embodying the invention and keyed to the head.

Fig. 2 is a plan view of a part of the shoe showing the additional lug.

Fig. 3 is a transverse sectional view on the line 3-3 of Fig. 2.

Fig. 4 is a detail perspective view of the strap lug. I r 7 Referring to the drawing, 5 is the body of the shoe, 6 is the back platewhich is embedded in the body at the back thereof, and '7 is the usual.

center attaching lug. The body is usually made of cast iron and the back plate of ductile metal but other materials may be used and the body may beprovided with inserts of any kind. The back plate may be of any suitable construction 7 and it is provided with recesses 8, 8 at its side edges. An additional lug is located between the center lug 7 and one end of the shoe. and it comprises a bent metal strap 9 which has diverging downwardly extending legs 10 with the extremi-l ties thereof directed inwardly and forming feet 10'. The strap lug engages the back 6 at the recesses 8, 8 and thefeet project inwardly beneath the back to anchor the strap to the back and to the body of the shoe. The recesses 8, 8

permit the body metal to flow during the casting operation beside the legs of the strap lug to form projections 11, 11 and some of the body metal will flow along the inside of the legs and form projections 12, 12in the angles between the legs and the back. These projections 11, 12 reenforce and strengthen the strap lug. The lug is tapered, 3 being narrow at the top, but it provides a key opening of sufiicient width at the top to accommodate the key; and this'enables the projections 11 to be made wider at the top than if the legs of the strap lug were parallel. The enlarged projections provide a greater bearing'surfa'ce of cast iron to engage the projection on the brake head. The size of the projections 12 within the strap lug depends upon the inclination of the legs and the desired size of the keyway opening in the additional lug.

The brake head13 has projections 14 to receive the center lug of the shoe therebetween. The end portions 15, 15 of the brake head are arranged to engage the end portions of the shoe at the back thereof. Between each projection 14 and the end portion of the head'there is a recess 16 in the head and the additional lug of V the shoe is arranged in one of these recesses. The recesses in the head are alike, or substantially alike,'and the shoe is made interchangeable end for end so that the additional lug will fit in either of the recesses 16. The strap lug must be of suflicient height so that the key opening therein will easily receive the fastening key, but the additional lug must be made so that it will fit in brake heads of different kinds and some brake heads have, the recesses 16 provided with inclined'bottom walls which will not accommodate an attaching lug of ordinary construction and permit the shoe to seat properly in the head. To overcome this and still provide a key opening of necessary height in the additional lug, I arrange the strap lug 9 forward so that the inner edge 9' of its top will be substantially fiush with the inner faces 11 of the projections 11, 11, Figs. 1 and 2. The strap forming the strap lug must be of suflicient width to cooperate with the center attaching lug to hold the shoe in the head and by this construction I am enabled to use a strap of desired width for the strap lug because the location of the strap lug as described will space the rear edge 9 of its top away from the bottom 16 of the recess 16 in the head. The corners, of the projections 11 are preferably rounded at 11". Thus I provide a strong and substantial additional lug with the parts thereof disposed and arranged in a novel mannerto enable this lug to fit in different kinds of brake heads and especially in those brake heads where the recess to receive the additional lug is of limited area at its bottom and has an inclined bottom wall. This permits a shoe to seat properly in a head wherein the recess 16 has aninclined bottom wall 16, as shown in Fig. 1. The additional lug cooperates with the center lug to no Y distribute the lug bearing surface of the shoe on the two projections 14: of the head and, consequently, the wear of the connecting parts of the shoe and head is distributed over a greater bearing surface area than if the additional lug was omitted. This prevents the shoe from becoming loose in the head due to excessive Wear at restricted contact surfaces and thereby maintains the shoe in proper position in the head and reduces vibration of the shoe in the head and prolongs the life of the shoe. Since it is necessary to provide shoes which can be used on different kinds of brake heads with which cars are equipped, it is important that the additional lug shall be so made that it can fit the recesses inthe heads as they are now made and my invention provides an additional lug which will fit in heads having inclined bottom walls as well as other heads provided with larger recesses. The inner edge 9' of the strap lug 9 will bear against the adjacent projection 14 of the head, but so also will the inner faces 11 of the projections l1, l1 and since these faces 11' are much greater in area than the edge 9 of the strap lug they will protect the projection 14 from excessive wear by the strap log 9'. In Fig. 1, I have shown the center lug and the additional lug contacting at the left with the projections 14. Some clearance is always provided for between the shoe lugs and the head and this clearance space is shown at the right of the center lug and the additional lug in Fig. 1. The shoe may be shifted to the right relative to the head so that this clearance space will appear at the left of the shoe lugs. This will indicate the pos sibility of slight lengthwise movement of the shoe on the head but this is not objectionable in service and it is important that provision should be made in the shoe lugs and in the head to provide for slight variations in dimensions. However, in either position of the shoe lugs in the head and during any wear at the contacting bearing surfaces between the shoe lugs and the head the inner edge of the additional strap lug will not unduly wear the projection on the head and the outer edge of the additional strap lug will not Wear the head at all, or at least to any appreci- 30 able degree.

I do not limit the invention to the particular embodiment of the invention shown in the drawing for the purpose of illustrating the invention for this application and I reserve the right 5 to make all such changes in the form, construction and arrangement of parts which may be necessary or desirable to adapt the invention for different shoes and difierent heads and within the scope of the following claim.

I claim:

The combination with a brake head having spaced projections to receive the attaching lug ,of a brake shoe therebetween and end portions to engage the end portions of the shoe at the back thereof, said brake head having a recess between one end portion and the adjacent projection and said recess having an inclined bottom wall, a brake shoe having a body, anattaching lug, a back plate embedded in the body, 1 0 a strap lug to enter said recess in the head and comprising a strap bent to form a high keyway and anchored to the back and to the body, parts of the body formingprojections alongside the strap lug, the top of said strap lug extending 55 above the body projections and that edge of said top adjacent the attaching lug being substantially flush with the corresponding faces of "the body projections, the opposite edge of the top of the strap lug being spaced from the corre: 131D sponding faces of said projectionsto clearthe bottom wall of the recess in the head, and-a tapered key extending thro ugh the lugs on the shoe and the projections on the brake head to fasten the shoe to the head. 1E5

ALBERTVNELSON. 

